The objective of this application is to unbiasedly identify regulators essential for programming intrinsic neuronal resistance to apoptosis. Apoptosis is a ubiquitous regulated cell death pathway controlling cell turnover and tissue homeostasis in metazoans. A longstanding issue is how neurons suppress apoptosis in favor of longevity. Previous studies on neuronal regulation of apoptosis have focused on why and how extrinsic survival cues help establish and maintain neural circuits through the control of cell death. While these inspiring studies delineate how neurons compete for survival at the time of circuit formation, important questions remain unresolved, i.e., whether neuronal apoptosis sensitivity is genetically determined. In our preliminary studies, we have found that neuronal resistance to apoptosis is intrinsically programmed before circuit formation by depletion of pro-apoptotic mitochondrial protein BAK1. We further found that BAK1 expression is controlled at the RNA level through robust alternative splicing mechanisms. The critical question is: what factors program Bak1 splicing? Identification of these factors will have significant impacts and enable new investigations of neuronal cell death controls in various settings. The proposed study will generate new tools and develop robust cell-based methods to systematically identify regulators of Bak1 splicing. We will integrate experimental and computational approaches to accelerate discoveries that would otherwise be limited and less sensitive. Our team has demonstrated successful collaborations researching cell death, neuronal survival, and RNA molecular genetics in the brain, and expect the proposed research to be fruitful. By revealing novel regulatory mechanisms of apoptosis and associated genetic factors, our findings may inform strategies for enhancing cell survival and tackling neurodegenerative diseases. Completion of the proposed study will also provide proof-of-principle for our broadly applicable strategy to study any alternative exons.